Magnetic resonance imaging of solid dental restoration materials using 3D UTE sequences: visualization and relaxometry of various compounds

• Published in: Magma (New York, N.Y.) N.Y.), 2013-12, Vol.26 (6), p.555-564
• Main Authors: Grosse, Ulrich, Syha, Roland, Papanikolaou, Dimitrios, Martirosian, Petros, Grözinger, Gerd, Schabel, Christoph, Schick, Fritz, Springer, Fabian
• Format: Article
• Language: English
• Subjects: Biomedical Engineering and Bioengineering; Computer Appl. in Life Sciences; Dental Materials - chemistry; Dentin - chemistry; Health Informatics; Humans; Imaging; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Medicine; Medicine & Public Health; Molar - pathology; Molar - physiology; Radiology; Reproducibility of Results; Research Article; Signal-To-Noise Ratio; Solid State Physics; Tooth - pathology; Tooth - physiology
• ISSN: 0968-5243; 1352-8661
• DOI: 10.1007/s10334-013-0373-8

Object Due to an increasing scientific interest in MR-imaging of carious lesions and teeth, an accurate signal characterization of dental restoration materials is necessary for optimization of MR sequence protocols and evaluation of material degradation. Therefore, signal yield and relaxation behavior of common dental restoration materials in comparison to those of dentine of extracted human teeth were assessed in vitro by ultrashort echo time (UTE) sequences. Materials and methods Eighteen material samples and dentine of two freshly extracted human teeth were investigated on a 3T whole-body clinical MR-scanner. Transverse ( T 2*) and longitudinal relaxation times ( T 1) were quantified using a recently published modified Ernst equation that takes relevant in-pulse relaxation effects into account. Results All investigated samples could be successfully visualized but maximum signal yield was highly variable between samples. T 1-values of the investigated dental restoration materials ranged between 28 and 365 ms, whereas T 2*-values ranged between 96 and 917 μs. In contrast, T 1-values of dentine ( T 1 = 545 ms ± 299 ms) were higher, while T 2*-values ( T 2* = 478 μs ± 271 μs) showed similar values. Conclusions Dental restoration materials and dentine of extracted human teeth can be visualized by UTE sequences and show a broad range of signal yield and relaxation times.